Any large business that's remotely in competition with Amazon corp is (rightfully) scared by Amazon's use of marketplace sellers' data to compete with them, and don't host on AWS, because they're afraid of Amazon using AWS data(that they have complete access to) to compete with them. So this goes for almost all retailers, grocery stores etc.
Yup, this is why major retailers (Walmart etc) don't use Amazon cloud services and instead use a competitor. I believe Walmart and some other large retailers use Azure but the retail industry in general is split between Azure & GCP for their cloud computing needs because they don't want to feed their competitor.
